The scientists who conducted the study are still unsure why the magnetic field is weakening.

HAHAHAhahah! Sorry, yeah, maybe they don't have internet or something, because the Earth's magnetic moment (overall dipole field strength) has been documented as weakening for the last couple centuries. Yes, we are in the throws of a magnetic pole inversion, as has happened at least several hundred times in the history of our planet. In fact, we are overdue, as far as the geological records are concerned. The poles aren't so much "getting ready to flip", we are seeing the manifestations of the early stages of this process. The field will continue to grow more chaotic/weaker (overall) in the next few thousand years, and will eventually realign with the opposite polarity.

It is true that the Earth will be exposed to greater levels of both solar and galactic cosmic ray radiation during this process, and it's only going to get worse, but I'm sure humanity will weather it out.